Implantable pump system

ABSTRACT

A controller module for an implantable pump system which has a pump motor includes a processor, a motor controller electrically coupled to the processor and adapted to power the pump motor such that the pump motor operates at a desired speed. The motor controller outputs digital representations of the pump motor operating parameters to the processor. A first memory device is coupled to the processor for storing the digital signals representing the pump motor operating parameters. The controller module further includes a user interface. The controller module may be coupled to a data acquisition system, which provides power and exchanges data with the controller module. The controller module may alternately be coupled to a home support system which provides power for the controller module and storage for system components.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional PatentApplication No. 60/060,665, entitled “Implantable Pump System,” filedOct. 2, 1997, by the same inventors, which is incorporated herein byreference in its entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates generally to pump control systems and, morespecifically, to a pump control system for an implantable blood pump.

[0004] 2. Description of Related Art

[0005] Implantable blood pump systems are generally employed either tocompletely replace a human heart that is not functioning properly, or toboost blood circulation in patients whose heart still functions but isnot pumping blood at an adequate rate. Known implantable blood pumpsystems are primarily used as a “bridge to transplant.” In other words,existing blood pump system applications are mainly temporary fixes,intended to keep a patient alive until a donor is available. However,the shortage of human organ donors, coupled with improvements in bloodpump reliability make long-term, or even permanent blood pumpimplementations a reality. The estimated need for a relatively simple,long-term ventricle assist device (VAD) is presently projected atbetween 50,000 and 100,000 patients per year in the United States alone.

[0006] Despite this need, existing implantable pump systems have notbeen satisfactory for long term use. Known systems of the continuousflow type are designed primarily for use in a hospital setting. Thesesystems typically include the implanted pump device, a power source suchas a rechargeable battery, a motor controller for operating the pumpmotor, and an external operator console. While some existing implantablepump systems allow for operation while decoupled from the operatorconsole, operating these systems “stand-alone” can be a risky endeavor.This is due, at least in part, to the lack of an adequate user interfacewhen the system is decoupled from the console.

[0007] Prior art blood pump systems generally only include electronicsfor operating the pump when disconnected from the console. Often, theuser interface is limited to a green light indicating that the system isoperating, or a red light indicating that the system is not operatingproperly. There are no provisions for displaying system parameters,diagnostic messages, alarm messages, etc. Further, known systemstypically lack memory capabilities. Hence, when a technician attempts todiagnose a prior art blood pump system after the red light indicated asystem failure, there is no record of the system conditions related tothe failure.

[0008] Further, even when an implantable continuous flow pump is coupledto an operator console, relevant system parameters are missing. Forexample, the operator consoles of known continuous flow pump systems maymonitor pump parameters such as voltage level, current level, pumpspeed, etc. These parameters, however, do not provide all the necessaryinformation to properly monitor a system that is as complicated as thehuman circulatory system. The system can be better assessed if pumpparameters are analyzed in conjunction with other factors, such as bloodflow rate, blood pressure or vibro-acoustic signatures. It is even moredesirable to monitor all of these parameters together in real time.Unfortunately, known blood pump systems typically lack the ability tointegrally analyze these data in real time.

[0009] Moreover, prior blood pump systems are not conducive to long-termuse outside an institutional setting. As discussed above, known systemsrequire a large, fixed operator console for the system to function.While prior art operator consoles may be cart mounted to be wheeledabout the hospital, at home use of known systems is difficult at best.

[0010] Other problems of prior pump systems that have limited theirmobility and use to relatively short times are related to motorcontroller size and shape limitations necessary for convenient mobility,weight limitations for implantation to avoid tearing of implant graftsdue to inertia of sudden movement, high power consumption that requiresa larger power supply, complex Hall Effect sensors/electronics forrotary control, the substantial desire for minimizing percutaneous(through the skin) insertions, including support lines and tubes, andhigh cost effectively.

[0011] Thus, there is a need for an implantable pump control system thataddresses the shortcomings associated with the prior art.

SUMMARY OF THE INVENTION

[0012] A controller module for an implantable pump system which includesa pump having an electric motor is presented in one aspect of thepresent invention. The controller module includes a microprocessor, amotor controller electrically coupled to the microprocessor and adaptedto power the pump motor such that the pump motor operates at a desiredspeed. The motor controller outputs digital representations of the pumpmotor operating parameters to the microprocessor. A first memory deviceis coupled to the microprocessor for storing the digital signalsrepresenting the pump motor operating parameters. The controller modulefurther includes a user interface. In one embodiment, the user interfaceincludes an LCD display and a keypad. In a further embodiment, arechargeable battery is included for powering the controller module.

[0013] In another aspect of the present invention, a data acquisitionsystem includes a primary power supply and a computer. The dataacquisition system is adapted to be removably coupled to the controllermodule such that the power supply provides power to the controllermodule when the data acquisition device is coupled to the controllermodule. The computer is programmed to exchange data with the controllermodule when the data acquisition device is coupled to the controllermodule.

[0014] In yet another aspect of the invention, a patient home supportsystem includes a power supply and a battery charger adapted to receiveand charge the rechargeable battery. A first connector is adapted toremovably couple the home support system to the controller module suchthat the power supply provides power to the controller module when thehome support device is coupled to the controller module.

[0015] In a still further aspect of the invention, a method ofcontrolling an implanted pump includes the acts of coupling a controllermodule to the implanted pump. The controller module includes amicroprocessor, a display device, a user input device, and a digitalmemory. The method further includes collecting operating parameters ofthe implanted pump, displaying the collected parameters on the displaydevice as selected by a user via the input device, storing the collectedparameters in the digital memory, and displaying the stored parameterson the display device as selected by a user via the input device.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Other objects and advantages of the invention will becomeapparent upon reading the following detailed description and uponreference to the drawings in which:

[0017]FIG. 1 is a block diagram of a ventricle assist device (VAD)system in accordance with an embodiment of the invention;

[0018]FIG. 2 illustrates an implantable heart pump in accordance withone embodiment of the invention;

[0019]FIG. 3 is a block diagram of the controller module of anembodiment of the invention;

[0020]FIG. 4 is a perspective view of an exemplary controller modulecase;

[0021]FIG. 5 illustrates a vest in accordance with an embodiment of theinvention for holding components of the implantable pump system;

[0022]FIG. 6 illustrates an embodiment of a motor speed control circuitin accordance with an embodiment of the invention;

[0023]FIG. 7 illustrates an embodiment of a battery detect circuit inaccordance with an embodiment of the invention,

[0024]FIG. 8 illustrates an embodiment of a power source control circuitin accordance with an embodiment of the invention;

[0025]FIG. 9 illustrates an embodiment of a clinical data acquisitionsystem in accordance with the invention;

[0026]FIG. 10 illustrates an embodiment of a patient home support systemin accordance with the invention; and

[0027]FIG. 11 illustrates an exemplary PHSS connection system inaccordance with the invention.

[0028] While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof have been shown by wayof example in the drawings and are herein described in detail. It shouldbe understood, however, that the description herein of specificembodiments is not intended to limit the invention to the particularforms disclosed, but on the contrary, the intention is to cover allmodifications, equivalents, and alternatives falling within the spiritand scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

[0029] Illustrative embodiments of the invention are described below. Inthe interest of clarity, not all features of an actual implementationare described in this specification. It will of course be appreciatedthat in the development of any such actual embodiment, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which will vary from one implementation toanother. Moreover, it will be appreciated that such a development effortmight be complex and time-consuming, but would nevertheless be a routineundertaking for those of ordinary skill in the art having the benefit ofthis disclosure.

[0030] System Overview

[0031] Turning to the figures, and in particular to FIG. 1, a ventricleassist device (VAD) system 10 in accordance with an embodiment of thepresent invention is illustrated. The VAD system 10 includes componentsdesigned to be implanted within a human body and components external tothe body. The components of the system 10 that are implantable include arotary pump 12 and a flow sensor 14. The external components include aportable controller module 16, a clinical data acquisition system (CDAS)18, and a patient home support system (PHSS) 20. The implantedcomponents are connected to the controller module 16 via a percutaneouscable 22. The controller module 16 may be mounted to a support device,such as a user's belt 23 or to a vest worn by the user. Alternatively,the controller module 16 may be placed on the CDAS 18 or placed on anightstand when the user is in bed. A spare controller module 16 may bestored in the PHSS 20. The controller module 16 includes two connectors24 and 26 for coupling to one or more batteries 28, which provide powerfor the controller module 16 when in a stand-alone mode. The system 10may further include a battery charger (not shown in FIG. 1). The sameconnectors 24, 26 also may couple the controller module to either theCDAS 18 or PHSS 20.

[0032] In an embodiment of the invention, the system 10 is controlled inan open loop fashion where a predetermined speed is set and the flowrate varies according to the pressure differential across the pump 12.The pump 12 is controlled in a closed loop fashion, wherein the actualpump speed is fed back to the controller module 16, which compares theactual speed to the desired predetermined speed and adjusts the pump 12accordingly.

[0033] In other embodiments, the controller module 16 is programmed suchthat closed loop, physiologic control methods are implemented by thesystem 10. In one embodiment, the controller module 16 may vary the pump12 speed according to the cardiac cycle (triggered either by electricalsensors or by real-time analysis of the pump 12 speed (RPM) or current).In one implementation, the pump 12 is used in conjunction with a valvein the graft coupled to the implanted pump 12 outflow. The pump speed isincreased synchronously with the heart during systole since high pumpspeed while the valve is closed would waste energy. In anotherimplementation, a mean low flow through the pump 12 is desired, forexample, 2-3 liters per minute, and there is no valve in the outflowgraft. At this condition, the pump speed is too low to stop the negativeflow through the pump during diastole, so it would be desirable toincrease the pump speed asynchronously with the heart to prevent thisreverse flow and still maintain a relatively low mean flow.

[0034] The controller module may further be used for much lowerfrequency physiologic control as compared to the implementationsdescribed above. This lower frequency control adjusts the pump 12 forevents such as sleeping, normal activity or high energy exertion. Inthese cases, the pump 12 average speed is adjusted in order to adjustthe mean flow through the pump 12. Alternately, the high and lowfrequency control schemes may be combined, employing high frequencycontrol based on each cardiac cycle and low frequency control based onblood flow requirements. Still further, the controller module 16 mayused in conjunction with a cardiac output measuring device. Thecontroller module 16 may be programmed with cycles to incrementallyreduce the pump speed when the cardiac output measuring devicedetermines to what extent the patient's heart has recovered while beingassisted.

[0035] VAD Pump

[0036] The system 10 of an embodiment of the invention may incorporatean implantable continuous-flow blood pump 12, such as the variousembodiments of axial flow pumps disclosed in U.S. Pat. No. 5,527,159 orin U.S. patent application Ser. No. 08/766,886, both of which areincorporated herein by reference in their entirety. An implantablecentrifugal pump also would be suitable for use in other embodiments ofthe invention. In still further embodiments, pulsatile pumps areemployed.

[0037] An example of a blood pump 12 suitable for use in an embodimentof the invention is illustrated in FIG. 2. The exemplary pump includes apump housing 32, a diffuser 34, a flow straightener 36, and a brushlessDC motor 38, which includes a stator 40 and a rotor 42. The housing 32includes a flow tube 44 having a blood flow path 46 therethrough, ablood inlet 48, and a blood outlet 50.

[0038] The stator 40 is attached to the pump housing 32, is preferablylocated outside the flow tube 44, and has a stator field winding 52 forproducing a stator magnetic field. In one embodiment, the stator 40includes three stator windings and may be three phase “Y” or “Delta”wound. The flow straightener 36 is located within the flow tube 44, andincludes a flow straightener hub 54 and at least one flow straightenerblade 56 attached to the flow straightener hub 54. The rotor 42 islocated within the flow tube 44 for rotation in response to the statormagnetic field, and includes an inducer 58 and an impeller 60.Excitation current is applied to the stator windings 52 to generate arotating magnetic field. A plurality of magnets 62 are coupled to therotor 42. The magnets 62, and thus the rotor 42, follow the rotary fieldto produce rotary motion.

[0039] The inducer 58 is located downstream of the flow straightener 36,and includes an inducer hub 64 and at least one inducer blade 66attached to the inducer hub 64. The impeller 60 is located downstream ofthe inducer 58, and includes an impeller hub 68 and at least oneimpeller blade 70 attached to the impeller hub 68. The diffuser 34 islocated within the flow tube 44 downstream of the impeller 60, andincludes a diffuser hub 72 and at least one diffuser blade 74 attachedto the diffuser hub 72. The exemplary pump further includes a frontbearing assembly 76 attached to the flow straightener hub 36.

[0040] Controller Module

[0041] The controller module 16 of an embodiment of the presentinvention is illustrated in greater detail in FIG. 3 in block diagramform. In one embodiment of the invention, the controller module 16 ispackaged in an ergonomic case 78 as illustrated in FIG. 4.

[0042] The controller module 16 includes a processor, such as amicrocontroller 80, which in one embodiment of the invention is a modelPIC16C77 microcontroller manufactured by Microchip Technology. Themicrocontroller 80 is coupled to a communications device 81 such as anRS-232 driver/receiver as is known in the art, and a hardware clock andcalendar device 82, which contains clock and date information, allowingthe controller module 16 to provide real-time clock and calendarinformation. The microcontroller 80 communicates with the hardware clock82 via the I²C protocol. The microcontroller 80 also is programmed witha selftest routine, which is executed upon application of power to checkcomponents of the controller module 16.

[0043] The controller module 16 includes first and second connectors 24,26 for coupling the controller module 16 to a power source, such as abattery 28, or the CDAS 18 or PHSS 20. In an embodiment of theinvention, the connectors 24, 26 include a break-away feature, such thatthe connectors 24, 26 disengage themselves if a given force is applied.For example, if a battery pack connected to the controller module 16falls on the floor, the connector will disengage rather than pull thecontroller module and in turn, tug on the percutaneous cable.

[0044] In one embodiment of the invention, the controller module 16 andthe batteries 28 are contained in a support device comprising a vest 210worn by the patient, illustrated in FIG. 5. The vest 210 includes afirst pocket 212 for holding the controller module 16 and two batterypouches 214 for holding two batteries 28. The battery pouches 214 mayinclude integral connectors 216 adapted to receive and connect thebatteries 28 to cables 218 which are coupled to the controller moduleconnectors 24, 26. The cables 218 may be internal to the vest 210,accessible through openings secured by a fastener, such as a Velcrofastener (not shown). The battery pouches 214 also include covers 220 tofurther protect the batteries 28 held within the battery pouches 214. Aparticular embodiment includes a PHSS connector on one of the batterypouches 214, to which a cable connects to couple the controller module16 to the PHSS 20. In other embodiments, the controller module 16 andthe batteries 28 are adapted to be connected to a belt worn by thepatient, and in still further embodiments, the belt may includesuspenders attached thereto to provide support for the belt.

[0045] Motor Controller

[0046] A motor controller 84 is coupled to the microcontroller 80, andthe motor controller 84 is coupled to the pump 12. The operation of thebrushless DC motor 38 of the present invention requires that current beapplied in a proper sequence to the stator windings 52. Two statorwindings 52 have current applied to them at any one time, and bysequencing the current on and off to the respective stator windings 52,a rotating magnetic field is produced. In an embodiment of theinvention, the motor controller 84 senses back electro motive force(EMF) voltage from the motor windings 52 to determine the propercommutation phase sequence using phase lock loop (PLL) techniques.Whenever a conductor, such as a stator winding 52, is “cut” by movingmagnetic lines of force, such as are generated by the magnets 62 of thebrushless DC motor 38, a voltage is induced. The voltage will increasewith rotor speed 42. It is possible to sense this voltage in one of thethree stator windings 52 because only two of the motor's windings 52 areactivated at any one time, to determine the rotor 42 position.

[0047] An alternative method of detecting the rotor 42 position relativeto the stator 40 for providing the proper stator winding 52 excitationcurrent sequence is to use a position sensor, such as a Hall effectsensor (not shown). However, adding additional components, such as Halleffect sensors, requires additional space, which is limited in anyimplanted device application. Further, using a position detection deviceadds sources of system failures.

[0048] The motor controller 84 switches a series of power switchingdevices 86 to regulate the stator winding 52 current. In one embodiment,the power switching devices 86 comprise metal oxide semiconductor fieldeffect transistors (MOSFETs).

[0049] The embodiment illustrated in FIG. 3 further includes a pumpmotor speed control circuit 88 coupled to the microcontroller 80 toreceive inputs regarding pump operation parameters. The speed controlcircuit 88 is coupled to the motor controller 84 through a switchingdevice 90, which couples either the speed control circuit 88 or ahardware-implemented “safe mode” speed setting 92, which is independentof the microcontroller 80.

[0050] The switching device 90 is actuated by a microprocessor failuredetector 94, which may comprise an external “watchdog” timer (not shownin FIG. 3) such as a monostable multivibrator, which continuouslymonitors the microcontroller 80. Any watchdog timers internal to themicrocontroller 80 are disabled. Alternatively, the switching device 90may be actuated by a safety plug 96 which is adapted to plug into eitherof the controller module connectors 24, 26. The external watchdog timeris periodically reset by the microcontroller 80 during normal controllermodule 16 operation. In the event that the microcontroller 80 fails, thewatchdog timer will not be reset. Upon the watchdog timer expiration,the watchdog timer activates the switching device 90, bypassing themicrocontroller 80 and setting the pump 12 to a predetermined speedsetting 92. This insures that the pump 12 continues to operate. In afurther embodiment, the watchdog timer, upon sensing a failure, triggersan emergency clamp and shuts down the pump 12. The emergency clampprevents backward flow through the pump 12.

[0051]FIG. 6 illustrates a schematic diagram of a motor control circuit200 in accordance with an exemplary embodiment of the invention. Themotor speed control circuit 200 includes the motor controller 84, thespeed control circuit 88, the fail detector 94, the switching device 90and the hard code speed 92 from FIG. 3.

[0052] The failure detector 94 includes a watchdog timer 210 coupled tothe switching device 90. Suitable watchdog timers and switching devicesinclude, for example, a model MAX705 monostable multivibrator and amodel MAX4514 single pole-single throw CMOS analog switch, respectively,both available from Maxim Integrated Products. In operation, the outputof the watchdog timer 210 is logically high during normal systemoperation (the microcontroller 80 functioning properly), and logicallylow when a malfunction or failure of the microcontroller 80 is detected.

[0053] During normal operation, the microcontroller 80 periodicallyprovides a watchdog timer reset signal to the input of the watchdogtimer 210, which resets the watchdog timer 210, and forces its output211 logically high. The output 211 of the watchdog timer is coupled tothe control input 91 of the switching device 90. In the exemplaryembodiment illustrated in FIG. 6, the switching device 90 is configuredas a normally open switch. Therefore, the logically high signal at thecontrol input 91 maintains the switching device 90 in a closed state,allowing the microcontroller 80 to control the pump 12 in accordancewith user input. If the watchdog timer 210 does not receive its periodicwatchdog timer reset signal, after a predetermined time period (forexample, one second), it will time-out and its output 211 will togglefrom a logically high state to a logically low state. The logically lowstate at the control input 91 of the switching device 90 will decouplethe microcontroller 80 from the motor controller 84 by opening theswitching device 90. Alternatively, the switching device 90 may beoperated by the safety plug 96 to manually decouple the microcontroller80 from the motor controller 84.

[0054] In the embodiment illustrated in FIG. 6, the motor controller 84comprises a Micro Linear model ML4425 motor controller. The motorcontroller 84 includes a voltage controlled oscillator, a pulse widthmodulated speed control circuit, a commutation logic control circuit, apulse width modulated current control circuit, MOSFET drivers, a backEMF sampler circuit, and a power fail detector. Additional detailsregarding the features and operation of the Micro Linear ML4425 motorcontroller are available in the appropriate Micro Linear specificationsheet.

[0055] The motor controller 84 further includes an onboard voltagereference V_(ref) and a speed control voltage input V_(spd) that is usedas the control reference voltage input for the motor speed controlphase-locked loop (PLL). In a typical implementation of a motorcontroller such as the Micro Linear ML4425 motor controller,predetermined voltage levels of V_(spd) correspond to desired motorspeeds, and the voltage level corresponding to the desired motor speedis input to the speed control voltage input V_(spd). With typical motorcontroller chips, however, motor speed control is based, at least inpart, on the relationship between the onboard voltage reference V_(ref)and the speed control voltage input V_(spd). In an embodiment employingthe Micro Linear ML4425 motor controller, in accordance with the circuitshown in FIG. 6, the onboard voltage reference V_(ref) output variesfrom 6.5 volts to 7.5 volts (6.9 volts nominal). Thus, if absolutevoltage levels corresponding to desired motor speeds are input to thespeed control voltage input V_(spd), the actual pump motor speed mayvary as much as ±20%.

[0056] To reduce this variation, the speed control circuit 88 shown inFIG. 6 provides a speed control voltage input V_(spd) level that isprogrammed to some proportion of the onboard voltage reference V_(ref)value, rather than an absolute voltage level. This removes the motorspeed control's dependency on the onboard voltage reference V_(ref)output. In a particular embodiment of the invention, this reduces thepump motor speed error from ±20% to approximately ±1%.

[0057] In the embodiment illustrated in FIG. 6, the speed control 88includes a digitally programmable electronic potentiometer 212 thatreceives inputs from the microcontroller 80. A model X9312T nonvolatiledigital potentiometer available from Xicor, Inc. is a suitable digitalpotentiometer. The “high” terminal 214 of the potentiometer 212 isdirectly coupled to the onboard voltage reference V_(ref) output of themotor controller 84, and the “low” terminal 216 is coupled to theonboard voltage reference V_(ref) through a voltage divider comprisingresistors 218, 220. In a specific embodiment, the resistors 218, 220comprise 1.02 kΩ and 1.5 kΩ resistors, respectively. The potentiometer212 thus provides a voltage output V_(set) at its “wiper” terminal thatvaries from about 0.6×V_(ref) to V_(ref). Allowing the speed controlvoltage input V_(spd) to equal the potentiometer 212 output voltageV_(set) yields a pump motor speed range of about 7,500 RPM to 12,500RPM.

[0058] The potentiometer 212 output voltage V_(set) is coupled to aninput of a first unity gain buffer amplifier 222, the output of which iscoupled, during normal operations, through the switching device 90 to aninput of a second unity gain buffer amplifier 224. The output of thesecond unity gain buffer amplifier 224 is connected to the V_(spd) inputof the motor controller 84 via a resistive divider comprising resistors226, 228. The values of resistors 226, 228 should be selected so as toachieve two desired ends: 1.) minimize the loading of the V_(set) signalwhen the microcontroller 80 is operating normally, and the switchingdevice 80 is therefore closed; and 2.) provide the proper V_(spd)voltage to realize the desired “safe mode” pump motor speed when theswitching device 90 is opened via the watchdog timer 210 or the safetyplug 96. In one particular embodiment, the predetermined “safe mode”speed setting is 8,500 RPM. Hence, the resistors 226, 228 comprise 31.6kΩ and 66.5 kΩ resistors, respectively, to achieve a V_(set) value equalto 0.68×V_(ref) when the switching device 90 is open.

[0059] The microcontroller 80 may further be programmed with a pumprestart feature for restarting the pump 12 in the event of a pumpfailure. The pump restart leaves the motor speed preset to its latestvalue. When the restart is activated, the microcontroller 80 initiates astart-up sequence of the motor controller 84, and locks a predeterminedtime period of pump performance data into the controller module'smemory. The controller module memory is discussed further below. If thepump 12 successfully restarts in response to the pump restart featurewithin a given time limit (10 seconds in one embodiment), a diagnosticalarm is enabled and the motor controller 84 returns the pump 12 to thelatest preset speed. If the pump 12 fails to restart, an emergency alarmis enabled and the restart sequence repeats. The microcontroller 80 maybe programmed to limit the number of restart attempts. In a particularembodiment, the controller module 16 limits the number of restartattempts to three for a given pump stoppage.

[0060] The microcontroller 80 includes a multiple channel analog todigital (A/D) converter, which receives indications of motor parametersfrom the motor controller 84. Thus, the controller module 16 may monitorparameters such as instantaneous motor current, the AC component of themotor current, and motor speed. In an embodiment of the invention, thecontroller module 16 incorporates low pass digital filtering algorithmsto calculate the mean values of parameters such as motor current to anaccuracy of ±1% of full scale.

[0061] The controller module 16 may include a ventricle collapse featurewhich detects excessive pump suction using the AC component of the motorcurrent parameter, wherein the microcontroller 80 is programmed todetect an excessive suction condition and in response thereto, reducethe pump rate until the condition is eliminated, or until the minimumpump speed is reached. The excessive pump suction detection featurediscriminates between a normal motor current wave form (quasi-sinusoidalafter filtering) and a suspect wave form (predictably distorted).Alternately, variations in motor speed may be used to detect excesssuction. Excessive pump suction parameters may be stored in anelectrically erasable programmable read only memory (EEPROM) 98 coupledto the microcontroller 80.

[0062] Controller Module Power

[0063] The controller module 16 receives power from the battery 28, theCDAS 18 or the PHSS 20 (see FIG. 1). The controller module 16 includesfirst and second connectors 24, 26, both of which are capable ofcoupling the battery 28 (which may be rechargeable), the CDAS 18 or thePHSS 20 to the controller module 16. In one embodiment of the invention,the batteries 28 comprise Duracell DR36 Powersmart Batteries, whichinclude an indicator that provides the battery's relative and absolutecharge levels, and an internal memory that stores battery data,including the number of charge and discharge cycles, the battery timeremaining, etc. The controller module 16 microcontroller 80 isprogrammed to query the battery 28 to obtain data related to thebattery. Thus, the microprocessor may be programmed to display an alarmmessage when a battery reaches a minimum charge or time level, or if abattery has not had a desired number of charge and discharge cycles.

[0064] The first and second connectors 24, 26 have first and secondbattery detect circuits 100, 102, respectively, coupled thereto. Thebattery detect circuits 100, 102 sense whether a battery 28, the CDAS 18or PHSS 20, or nothing is coupled to the connector 24, 26. The batterydetect circuits 100, 102 are coupled to a power source control circuit104. If either the CDAS 18 or PHSS 20 is coupled the connectors 24, 26,the power source control circuit 104 detects this and switches thesystem such that the CDAS 18 or PHSS 20, as applicable, provides powerto the controller module 16. If the batteries 28 are coupled to bothconnectors 24, 26, the battery 28 having the lower charge level (above aminimum level) is selected.

[0065] An embodiment of a battery detect circuit 100, 102 is illustratedin FIG. 7, which includes a battery detect portion 106 and a DAS detectportion 108. The DAS detect portion 108 detects whether the CDAS 18 orPHSS 20 is coupled to the connector. The DAS detect portion 108 receivesa first DAS connect input signal (DASCON1) from the first systemconnector 24. The DASCON1 signal input is provided to a first comparator110, which outputs a signal (DASPRES1) indicating whether the CDAS 18 orPHSS 20 is connected to the terminal. If the CDAS 18 or PHSS 20 iscoupled to the connector 24, DASPRES1 outputs a logically high signal,and a logically low signal is output if no device is coupled to theconnector 24. Simiarly, in the battery detect portion 106 of the circuit100, a first battery connect input signal (BATTCON1) is coupled througha fuse 112 to an input of a second comparator 114, which outputs asignal (BATTPRES1) that is logically high if a battery 28 is coupled tothe connector and above a predetermined minimum charge level. TheBATTPRES1 signal is logically low if there is no battery 28 present, orif the battery 28 is below the minimum charge level. The first andsecond comparators 110, 114 may comprise two comparators of an LTC1443quad comparator available from Linear Technology Corp. The remaining twocomparators may be used for the second battery detect circuit 102.

[0066] An embodiment of the power source control circuit 104 isillustrated in FIG. 8. The exemplary logic circuit 104 comprises aplurality of two-input NAND gates 116 and a plurality of inverters 118.For the circuit illustrated in FIG. 8, three 74HC00 quad NAND chipssupply the NAND gates 116, and a 74HC04 inverter chip supplies theinverters 118. Inputs to the logic circuit 104 include the DASPRES1 andBATTPRES1 signals from the first battery detect circuit 100, DASPRES2and BATTPRES2 signals from the second battery detect circuit 102, and abattery select signal (BATTSEL). In other embodiments, the power sourcecontrol circuit 104 is implemented in software using a programmablelogic device.

[0067] The BATTSEL signal is provided by the microcontroller 80. If eachof the connectors 24, 26 has a battery 28 attached, the microcontroller80 monitors the connected batteries 28 and selects the battery 28 withthe lower charge, as read from the battery pack, if the charge level isabove a desired, predetermined level. The microcontroller 80communicates with the batteries 28 via the I²C protocol. Themicrocontroller 80 queries the batteries 28 periodically to determinecharge status. In an embodiment of the invention, the batteries 28 arequeried upon connection and at intervals of approximately one minutethereafter. If the lower charged battery 28 falls below the minimumlevel, the power source control 104 switches to the higher chargedbattery 28. If the battery 28 coupled to the first connector 24 is to beselected, the microcontroller 80 outputs a BATTSEL signal that islogically high, and if the battery 28 coupled to the second connector 26is to be selected, BATTSEL is logically low. Moreover, if themicrocontroller 80 determines that one or both batteries 28 fall below agiven charge level, the microcontroller 80 may be programmed to shutdown selected components of the system 10, such as the flow meter 124,to conserve power.

[0068] The power source control circuit 104 provides two output signals,SELECT1 and SELECT2, which in response to the DASPRES1, BATTPRES1,DASPRES2, BATTPRES2 and BATTSEL input signals, indicate whether thecontroller module 16 is to be powered by the device coupled to therespective connector 24, 26. If the device coupled to the firstconnector 24 is selected to power the controller module 16, the SELECT1signal is logically high and the SELECT2 signal is logically low.Conversely, the SELECT1 signal is logically low and the SELECT2 signalis logically high if power is to be provided via the second connector26. The power source control 104 includes two switching devices (notshown) coupled to the SELECT1 and SELECT2 output terminals andresponsive thereto for connecting the controller module 16 to either thefirst or second connector 24,26.

[0069] Referring again to FIG. 3, an internal battery 120 provideslimited back-up power in the event of a complete power loss. In oneembodiment, the internal battery 120 powers the microcontroller 80 andalarms if power from the external batteries 28 is lost, and the internalbattery 120 also powers the clock/calendar 82 and the system prompts 98if the external batteries 28 are disconnected. Thus, power remainsavailable to critical functions and to activate an alarm signaling theloss of power.

[0070] Controller Module Memory

[0071] As shown in FIG. 3, a series of memory devices 122 areadditionally coupled to the microcontroller 80 to save system parametersin the event of an emergency, such as a pump shutdown. In one embodimentof the invention, the memory devices comprise three 128K banks of SRAM,which store pump parameters such as pump voltage, current, RPM and flow.The first of the three SRAM banks, segment 0, is the “looping bank,”which employs a continuous, circular buffer that continuously stores thecurrent performance data. Upon a predetermined event, such as a pumpshutdown and restart, the microcontroller 80 is programmed to transferthe data from the circular buffer to one of the other memory banks.

[0072] The second SRAM bank, segment 1, contains the pump performancedata prior to the first alarm or restart that occurs after initialpower-on or a clearing of segment 0 by the CDAS (CDAS communicationswith the controller module will be further discussed below). The thirdbank, segment 2, contains pump performance data prior to the most recentrestart event. After each restart event (or any alarm if segment 0 isclear) the data in the active looping bank are transferred to segment 0or segment 1, as appropriate. For example, following initial start-up,if the pump stops, the processor transfers the data from the memorysegment 0, the circular buffer, to memory segment 1. Assume that thepump then restarts. The pump performance data in the circular bufferassociated with any subsequent predetermined events are transferred frommemory segment 0 to segment 2, such that segment 2 always has the dataassociated with the most recent pump event.

[0073] In one embodiment of the invention, memory segments 0 and 1 eachstore 55 seconds of pump performance data segments, including pump speed(RPM), voltage, flow rate, instantaneous motor current and time.Further, sample rates for these parameters may be as follows:instantaneous motor current, 2000 samples per second; flow rate, 333samples per second; pump speed, 10 samples per second; and voltage, 10samples per second. The sampling resolution for these parameters iseight bits in one embodiment of the invention.

[0074] Each memory segment includes predetermined boundaries for eachsampled parameter. For example, pump motor current requires 110,000bytes to store 55 seconds at 2000 samples per second which may be storedin a predetermined memory array. Defining parameter boundaries in thisfashion allows a technician to request parametric data by reading arange of blocks. The last block in each memory segment contains timestamp information available from the real-time clock and calendar alongwith a start and stop memory pointer for each parameter.

[0075] Flow Meter

[0076] Another novel aspect of an embodiment of the present invention isthe inclusion of an integral flow meter 124, as shown in FIG. 3. Asdisclosed above, at least one flow sensor 14 is implanted down stream ofthe pump 12. Alternately, a flow sensor 14 may be integrated with thepump 12. A Custom 12A dual channel flow sensor available from TransonicSystems, Inc. is implanted downstream of the pump 12 in an embodiment ofthe invention. The flow meter 124, which may comprise a TransonicSystems, Inc. model FPT110 dual channel flow meter, is coupled betweenthe implanted flow sensor 14 and the microcontroller 80. The flow meter124 averages the data from the two flow sensor channels and outputs flowrate data to the microprocessor A/D converter (not shown), allowing themicroprocessor to monitor instantaneous flow rate. The flow signalamplitude of each flow meter channel is also provided to themicroprocessor to monitor system integrity.

[0077] Since the implanted flow sensor 14 is coupled to the flow meter124 of the controller module 16, a true measure of system performance(flow rate) is available for analysis, in addition to pump parameterssuch as pump speed. Further, since the flow meter 124 is an integralcomponent of the controller module 16, flow rate may be displayed on thecontroller module display (described below), and flow rate data may besaved in the controller module memory 122 for later analysis.

[0078] Providing a flow meter 124 as an integral component of theportable controller module 16 solves a significant shortcoming of priorart VAD and artificial heart systems, which typically do not capture anddisplay flow rate data on a portable device. Even if a known VAD orartificial heart system were to include an implanted flow transducer,prior art systems would require an external console to display andcapture the flow data. This valuable system information would be lostwhenever the system is not coupled to the external console. On the otherhand, the present invention provides a means to display and analyze flowrate data for all pump operating times, whether or not the controllermodule is connected to the CDAS.

[0079] Controller Module User Interface

[0080] The EEPROM 98 connected to the microcontroller 80, in addition tostoring excessive suction detection parameters, stores prompts andmessages for display and manipulation via a user interface 126 (notshown in FIG. 3). The microprocessor communicates with the EEPROM 98 viathe I²C protocol in one embodiment. As shown in FIG. 4, the userinterface 126 may comprise a display 128 and an input device 130. In oneembodiment, the controller module display 128 comprises a two-row,back-lit 16-character LCD display; two multicolored LEDs 132 whichindicate battery status; and an additional LED 134 which indicates whenthe unit is in the safemode. The input device 130 may include a keypad,which in an embodiment of the invention, includes two sealed keypadswitches to perform the functions of alarm silence and display scroll.The LCD 128 also contains a conventional backlight (not shown), which isautomatically lit either by pressing one of the keypad switches 130 orwhen an alarm is sounded. The LCD 128 is positioned within thecontroller module case 78 such that it is easily viewed by a userlooking down at the controller module 16 mounted on the user's belt orheld within the vest 210, or from a bedside when the controller module16 is located on a table or nightstand.

[0081] The display 128 may be configured to display messages in multiplelanguages. The message displays may be arranged such that predetermineddisplay character positions are reserved for displaying the parameter oralarm “label,” such as “PUMP SPEED.” These labels may be stored in oneor more languages in the message and parameter EEPROM 98. Otherpredetermined positions on the display 128 may be reserved fordisplaying the parameter value reading as received by the controllermodule.

[0082] In a particular embodiment, the default LCD message displayed isflow rate and power on the first display line and the percent ofcapacity or time remaining for each battery connected on the seconddisplay line. Alternately, if the flow meter 124 is disabled, motorspeed and motor power may be displayed on the first display line. If thecontroller module is coupled to the CDAS, the LCD displays “DASCONNECTED.” Other main LCD messages displayed include “PERFORMING SELFTEST,” and “VAD SYSTEM MODEL NUMBER,” which are toggled upon initialpower-up while the microprocessor executes the self test sequence.

[0083] The controller module 16 is also capable of displaying diagnosticmessages on the LCD 128. A user may scroll the diagnostic messages bypressing the display scroll keypad switch 130. The first depression ofthe display scroll key initially illuminates the backlight (if notpreviously lit), and all subsequent scroll key depressions continuouslyscan through the message displays. Diagnostic messages included in aparticular embodiment of the invention include the date, time and unitserial number; motor current; motor speed; received amplitudes of theflow sensor channels; excess suction enabled (or disabled); flow sensorenabled (or disabled) and physiological control enabled (disabled).

[0084] The controller module 16 also provides audible alarms and alarmmessages, which are displayed on the LCD. The audible alarm may usedifferent distinct sounds to indicate diagnostic and emergency events.The diagnostic alarm may have multiple volume levels and may repeat aseries of beeping tones which increase in rate and volume until answeredby pressing the alarm silence key. Pressing the alarm silence keysilences the audible alarm, but does not clear the alarm messagedisplayed on the LCD 128. In general, diagnostic alarms are providedwhen a measured parameter (PARAMETER) differs from a predeterminedparameter value (PARAMETER_(alarm)) by a threshold amount. ThePARAMETER_(alarm) and threshold values are stored in the EEPROM. TheEEPROM provides non-volatile storage for these important messages andsystem parameters. The emergency audible alarm may comprise a continuousbeep at maximum volume level to indicate the severity of the event. Ifboth diagnostic and emergency events occur simultaneously, themicroprocessor is programmed to sound only the emergency alarm.

[0085] The microprocessor is programmed to store some alarm messages inthe controller module 16 until acknowledged by an operator via the CDAS18. In an embodiment of the invention, the selected alarm message and atime stamp for the message are stored until acknowledged by the CDAS 18.The alarm displays in conjunction with the data regarding systemparameters associated with the first and last predetermined pump eventstored in the memory device 122 insure that ample data exists foranalysis by a physician or technician.

[0086] The multicolored battery status LEDs 132 may indicate variousbattery conditions. For example, a solid green indicates that thebattery is in use and blinking amber indicates a low charge level,expired battery, or battery disconnected. If the battery status LED isoff, the charged battery is connected but not presently in use, andalternating amber and green indicates the self test mode. The safe modeindicator 134 is activated by the watchdog timer 94 in the event of amicrocontroller 80 failure. Emergency alarms and diagnostic alarms foran embodiment of the invention are displayed in Table 1 and Table 2below. TABLE 1 Emergency Alarms Alarm condition Message Notes Pumpstopped PUMP STOPPED Controller failure CONTROLLER FAILURE Results insafe mode pump speed setting Both batteries BOTH BATTERIES disconnectedDISCONNECTED Patient interface VAD DISCONNECTED disconnected

[0087] TABLE 2 Diagnostic Alarms Alarm condition Message Notes Excesscurrent EXCESS CURRENT Motor current > I_(alarm) Low flow rate REDUCEDFLOW <2 liters/minute RATE Internal battery low LOW INTERNAL BATTERY LowMotor Speed MOTOR SPEED Motor RPM < REDUCED RPM_(alarm) Pump restartedPUMP RESTARTED Excess suction EXCESS SUCTION RPMS REDUCED Battery #1disconnected BATTERY #1 Battery indicator #1 DISCONNECTED flashes amberBattery #1 discharged BATTERY #1 Battery indicator #1 DISCHARGED flashesamber Battery #1 expired BATTERY #1 Battery indicator #1 EXPIRED flashesamber Battery #2 disconnected BATTERY #2 Battery indicator #2DISCONNECTED flashes amber Battery #2 discharged BATTERY #2 Batteryindicator #2 DISCHARGED flashes amber Battery #2 expired BATTERY #2Battery indicator #2 EXPIRED flashes amber

[0088] Clinical Data Acquisition System (CDAS)

[0089] An embodiment of the CDAS 18 is pictured schematically in FIG. 9.The CDAS includes a computer 128, which includes a processor 140, atleast one memory storage device 142, a video display 144 and an inputdevice 146, such as a computer keyboard. In one embodiment, the videodisplay 144 is an LCD. The CDAS 18 is mounted on a moveable cart 148such that the CDAS 18 can escort a patient during movements within thehospital. The CDAS 18 is configured for use within a hospital setting,and is not intended to go home with a patient having an implanted pump12. The CDAS 18 further collects and displays data from the controllermodule 16, sends comments and data to the controller module 16, andsupplies power to the controller module 16.

[0090] The primary power source for the CDAS 18 is 120 volt, 60 Hz ACpower, or 220 volt, 50 Hz AC power as from standard wall electricaloutlets. The CDAS 18 includes a medical grade power supply 149 such asis known in the art for providing power to the controller module 16. TheAC mains are isolated by a medical grade isolation transformer 150. TheCDAS 18 further includes a battery backed uninterruptable power supply(UPS) system 152. In one embodiment of the invention, the UPS 152 iscapable of operating the controller module 16 alone for eight hours andthe controller module 16 and CDAS 18 for one hour when AC power isunavailable.

[0091] The CDAS 18 provides an operator interface to the controllermodule in addition to the LCD 128 and controller module keypad 130. TheCDAS 18 includes a communications port 153, such as a standard RS-232communications port and an A/D converter 154. All data communicationbetween the CDAS 18 and the controller module 16 is electricallyisolated. A cable 155 couples the CDAS 18 to one of the controllermodule connectors 24, 26, through which the CDAS 18 provides power andcommunicates with the controller module 16. The cable 155 connects theCDAS power supply 149 to the battery detect circuit 100,102 associatedwith the appropriate controller module connector 24, 26. The same cable155 additionally couples the communications port 153 to the RS-232driver/receiver 81 and the digital to analog converter 154 to the flowmeter 124 and the motor controller 84.

[0092] Thus, the CDAS 18 is able to exchange commands and otherinformation with the controller module 16, such as digital data storedin the parameters and messages EEPROM 98 or the controller module memorydevices 122. Further, the CDAS 18 is directly coupled to the motorcontroller 84 and the flow meter 124 to receive real-time analog motorcurrent and flow data, respectively. The real-time analog data receivedmay be isolated and filtered, then displayed in real time on the CDASvideo display 144.

[0093] In an embodiment of the invention, digital data regarding pumpvoltage, current, RPM and flow data are stored in the controller modulememory device 128 and are downloaded to the CDAS 18 via the RS-232interface. The CDAS 18 may then plot this information on the videodisplay 144, and store the data in the CDAS memory device 142. Further,diagnostic and emergency messages may be downloaded and a log kept ofthese messages. The CDAS 18 is also coupled to the controller modulereal-time clock and calendar 82 so that these parameters may besynchronized with the controller module 18.

[0094] The CDAS 18 may further be coupled to other devices external tothe controller module 16. Examples of such devices may include anex-vivo blood pressure transducer for capturing and displaying bloodpressure information during surgery. An auxiliary contact microphone 158may be coupled to the CDAS 18 to capture and display acousticinformation for monitoring pump 12 condition. Thus, data in addition tothat provided by the controller module 16 may be captured, stored, anddisplayed by the CDAS 18.

[0095] The CDAS 18 further provides an interface for an operator tochange system parameters such as pump speed, alarm thresholds and excesssuction parameters, and to run test routines on the system. In anembodiment of the invention, the system access is password controlledbased on different user levels. For example, Level 1 users (patient) maybe allowed to view alarm messages and pump operating parameters; Level 2users (physician) may view alarm messages and pump operating parameters,and also make minor system changes such as adjusting pump speed; andLevel 3 users (technician) have access to all CDAS functionality.

[0096] Another function related to the CDAS 18/controller module 16interface involves diagnosing pump 12 problems. As discussed above, pumpparameters are stored for a predetermined time period prior to twoemergency events in the controller module memory. If, for example, thepump 12 fails while the controller module 16 is not connected to theCDAS 18, 55 seconds of pump performance data is stored in the controllermodule memory 122. When the controller module 16 is coupled to the CDAS18 subsequent to the failure, analysis of the pump parameters just priorto the failure may be essential for diagnosing the problem.

[0097] Examples of additional controller module 16 operations performedvia the CDAS 18 in an embodiment of the invention include programmingand verifying multilingual controller module LCD messages, real-timeclock/calendar, parameters for use by the excess suction feature, alarmparameters, and operational parameters. Further, a user may operate thepump motor, the excess suction feature, and the flow meter via the CDAS,or closed loop physiological system control may be activated.

[0098] Patient Home Support System (PHSS)

[0099] Known artificial heart and VAD systems rely on a large externalconsole for the bulk of the system operation. In the system of anembodiment in accordance with the present invention, the controllermodule includes processing, memory, and operator interface capabilities.Thus, the system 10 may be operated for an extended period independentof the CDAS 18 in a truly portable mode.

[0100] The PHSS 20 of an embodiment of the invention is illustrated inFIG. 10. The PHSS 20 is a portable device that can be hand-carried, asopposed to being moved on a cart as the consoles of prior art VADsystems. The PHSS 20 comprises a power supply 160 sourced by 120 volt,60 Hz AC power or 220 volt, 50 Hz AC power as from standard wallelectrical outlets. The AC mains are isolated by a medical gradeisolation transformer 162. The PHSS further includes at least onecompartment 164 having a connector (not shown) for receiving one or morebatteries 28. In an embodiment of the invention, the PHSS includes fourbattery compartments 164, each of the compartments 164 being coupled toan integral battery charger 30.

[0101] The PHSS 20 is coupled to the controller module 16 via a cable166. FIG. 11 illustrates the PHSS 20 connection to the controller modulefor one embodiment of the invention. The PHSS cable 166 is coupled tothe PHSS connector 222, which may be connected directly to one of thebattery connectors 216 or connected to a cable 218 between the batteryconnectors 216. The battery connectors 216 are coupled to the controllermodule connectors 24, 26. When the PHSS 20 is coupled to the controllermodule 16, the DASPRES1 or DASPRES2 signal of the power control circuit104 will be logically high. Therefore, the power control circuit 104will power the controller module 16 from the PHSS power supply. Thecontroller module 16 will then attempt to communicate via the RS-232interface with the connected device. Since the PHSS 20 does not includecommunications capabilities, the controller module 16 then knows thatthe PHSS 20 is connected rather than the CDAS 18.

[0102] The PHSS connector 222 further includes a logic device or circuit(not shown) for further managing the system power when the PHSS 20 iscoupled to the controller module 16. When the PHSS cable 166 is coupledto the PHSS connector 222, the controller module 16 is powered via thePHSS. Once the PHSS power connection is established, the batteries 28may be removed from the battery connectors 216. A message noting that itis safe to remove the batteries may be displayed on the LCD 128.

[0103] The batteries 28 are then placed in the battery compartments 164,where they either provide a back-up to the PHSS 20, or they arerecharged by the charger 30 contained within the PHSS 20. Using thebatteries 28 as a power back-up eliminates the need for an additionalback-up power supply, in turn reducing the size requirement and makingthe PHSS more economical. The PHSS connector 222 queries the batteries28 held in the compartments 164 to determine their respective chargelevels. In one embodiment, the battery with the highest charge providesa power back-up to the PHSS. The remaining battery is recharged. If therecharging battery's charge level reaches a point higher than theback-up battery 28, PHSS connector 222 reverses the battery 28 functionso the back-up battery 28 may now recharge.

[0104] The remaining battery compartments 64 may hold additional sparebatteries, which are either recharged or provide back-up to the PHSSpower supply as determined by the logic circuit within the PHSSconnector 222. The PHSS further includes an additional compartment 172for holding a spare controller module (not shown), and a storage space170 for holding spare cables and the like.

[0105] The above description of exemplary embodiments of the inventionare made by way of example and not for purposes of limitation. Manyvariations may be made to the embodiments and methods disclosed hereinwithout departing from the scope and spirit of the present invention.The present invention is intended to be limited only by the scope andspirit of the following claims.

What is claimed is:
 1. A controller module for an implantable pumpsystem including a pump having an electric motor, the controller modulecomprising: a processor; a motor controller electrically coupled to theprocessor, the motor controller adapted to power the pump motor suchthat the pump motor operates at a desired speed, the motor controlleradapted to output digital representations of pump motor operatingparameters to the processor; and a user interface coupled to theprocessor.
 2. The controller module of claim 1 further comprising apower source.
 3. The controller module of claim 1 further comprising atleast one connector for coupling the controller module to an externalpower source.
 4. The controller module of claim 1 further comprising ahardware clock and calendar device coupled to the processor.
 5. Thecontroller module of claim 1 further comprising a first memory devicecoupled to the processor for storing the digital data representingsystem operating parameters.
 6. The controller module of claim 1 whereinthe first memory device comprises an SRAM.
 7. The controller module ofclaim 1 wherein the first memory device comprises a plurality of memorybanks, and wherein at least one of the banks includes a circular bufferfor continuously storing real-time pump motor parameters in predefinedtime increments.
 8. The controller module of claim 7 wherein theplurality of memory banks comprises at least first and second memorybanks, first memory bank including the circular buffer, and wherein theprocessor is programmed to transfer the data from the first memory bankto the second memory bank upon a first predetermined event.
 9. Thecontroller module of claim 8 wherein the plurality of memory banksfurther comprises a third memory bank, wherein the processor isprogrammed to transfer the data from the first memory bank to the thirdmemory bank upon any predetermined events subsequent to the firstpredetermined event.
 10. The controller module of claim 9 wherein thepredetermined event comprises a pump restart.
 11. The controller moduleof claim 1 further comprising a failure detection device adapted todetect a processor failure, the failure detection device operable todecouple the processor from the motor controller in response to thedetected processor failure.
 12. The controller module of claim 1 whereinthe user interface includes a text display, and wherein the processor isprogrammed to selectively display data stored in the first memorydevice.
 13. The controller module of claim 12 further comprising asecond memory device coupled to the processor including digital datastored therein, and wherein the processor is programmed to selectivelydisplay the data on the text display.
 14. The controller module of claim1 , wherein: the motor controller includes a reference voltage outputterminal and a speed control voltage input terminal; and the controllerfurther comprises a pump speed control device adapted to calculate andprovide a voltage level to the speed control voltage input terminal as aproportion of the reference voltage to achieve a desired pump speed. 15.An implantable pump system comprising: an implantable blood pumpincluding a pump motor; and a controller module adapted to be coupled tothe blood pump, the controller module including a processor; a motorcontroller electrically coupled to the processor, the motor controlleradapted to power the pump motor such that the pump motor operates at adesired speed, the motor controller adapted to output digitalrepresentations of pump motor operating parameters to the processor; afirst memory device coupled to the processor for storing the digitalsignals representing pump motor operating parameters; and a userinterface.
 16. The implantable pump system of claim 15 wherein thecontroller module further includes at least one connector coupled to theprocessor, the implantable pump system further comprising a dataacquisition device including: a primary power supply; a computer; acable having first and second ends, the first end being coupled to thecomputer, the second end being adapted to be removably coupled to thecontroller module; the data acquisition device providing power to thecontroller through the cable; and the computer being programmed toexchange data with the controller module processor through the cable.17. The implantable pump system of claim 16 further comprising asecondary power supply.
 18. The implantable pump system of claim 16wherein the connector is further coupled to the first memory device andthe computer is programmed to exchange data with the first memorydevice.
 19. The implantable pump system of claim 16 wherein theconnector is further coupled to the motor controller and the computer isfurther programmed to receive data from the motor controller.
 20. Theimplantable pump system of claim 16 further comprising an implantableflow sensor, and wherein the controller module further includes a flowmeter adapted to be coupled to the implantable flow sensor; theconnector is further coupled to the flow sensor; and the computer isfurther programmed to receive data from the flow sensor.
 21. Theimplantable pump system of claim 16 further comprising a pressuretransducer adapted to be coupled to the computer.
 22. The implantablepump system of claim 16 further comprising a contact microphone adaptedto be coupled to the computer.
 23. The implantable pump system of claim15 where in the controller module further includes first and secondconnectors each coupled to the processor, the implantable pump systemfurther comprising at least one rechargeable battery and a home supportdevice including: a power supply; a battery charger; a first cablehaving a first end coupled to the power supply and a second end coupledto the first connector; and a second cable having a first end coupled tothe battery charger and a second end coupled to the second connector.24. The implantable pump system of claim 15 , further comprising adevice adapted to be worn by a user of the implantable blood pump, thedevice adapted to have the controller module connected thereto.
 25. Theimplantable pump system of claim 24 , wherein the device adapted to havethe controller module connected thereto comprises a belt.
 26. Theimplantable pump system of claim 24 , wherein the device adapted to havethe controller module connected thereto comprises a vest.
 27. A dataacquisition device for an implantable pump system including animplantable pump, a controller module coupled to the pump and includinga memory for storing data regarding operation of the implantable pump,the data acquisition device comprising: a primary power supply; acomputer; the data acquisition device adapted to be removably coupled tothe controller module such that the power supply provides power to thecontroller module when the data acquisition device is coupled to thecontroller module; and the computer being programmed to exchange datawith the controller module when the data acquisition device is coupledto the controller module.
 28. A home support device for an implantablepump system including an implantable pump, a controller module coupledto the pump having a memory for storing data regarding operation of theimplantable pump, and a rechargeable battery, the home support devicecomprising a power supply; a battery charger adapted to receive andcharge the rechargeable battery; and a first connector adapted toremovably couple the home support device to the controller module suchthat the power supply provides power to the controller module when thehome support device is coupled to the controller module.
 29. A method ofcontrolling an implanted pump comprising the acts of: coupling acontroller module to the implanted pump, the controller module includinga processor, a display device, a user input device, and a digitalmemory; collecting operating parameters of the implantable pump;displaying the collected parameters on the display device as selected bya user via the input device; storing the collected parameters in thedigital memory; and displaying the stored parameters on the displaydevice as selected by a user via the input device.
 30. The method ofclaim 29 wherein the digital memory is divided into a first memorysegment including a circular buffer and a second memory segment, whereinthe collecting act further comprises storing the collected data in thefirst memory segment; the method further comprising the acts of:continuously updating the stored operating parameters of the implantedpump such that a predetermined time period of the most recent data arestored in the first memory segment; and transferring a predeterminedtime period of the stored parameters from the first segment to thesecond segment upon a predetermined event.
 31. The method of claim 30wherein the transferring act further comprises the predetermined actbeing a pump failure.
 32. The method of claim 30 further comprising theacts of: providing a data acquisition system including a video displaydevice; transferring the collected pump parameters from the controllermodule to the data acquisition system; and displaying the pumpparameters on the data acquisition system video display device.
 33. Themethod of claim 32 further comprising the data acquisition systemincluding a memory storage device, the method further comprising theacts of: transferring the pump parameters stored in the controllermodule first memory segment to the data acquisition system memorystorage device; and displaying the pump parameters from the dataacquisition system storage device on the video display device.
 34. Themethod of claim 29 wherein the controller module further includes a flowmeter coupled to an implanted flow sensor, the method further comprisingthe acts of: collecting data from the flow meter; displaying thecollected flow data on the display device as selected by a user via theinput device; storing the collected flow data in the digital memory; anddisplaying the stored flow data on the display device as selected by auser via the input device.
 35. The method of claim 34 further comprisingthe acts of: providing a data acquisition system including a videodisplay device; transferring the collected flow data from the flowsensor to the data acquisition system; and displaying the flow data onthe data acquisition system video display device.
 36. The method ofclaim 35 further comprising the data acquisition system including amemory storage device, the method further comprising the acts oftransferring the flow data stored in the controller module digitalmemory to the data acquisition system memory storage device; anddisplaying the pump parameters from the data acquisition system storagedevice on the video display device.
 37. A support device for a person inwhich a blood pump is implanted, the device comprising: a first holderadapted to connect a control module for the implantable pump to thesupport device; and a second holder adapted to connect a battery forpowering the implantable pump and the control module to the device. 38.The support system of claim 37 , further comprising a belt adapted to beworn about the person, wherein the first and second holders are situatedon the belt.
 39. The support system of claim 37 , further comprising avest adapted to be worn by the person, wherein the first and secondholders comprise first and second pockets in the vest.
 40. The supportsystem of claim 37 , further comprising at least one cable extendingbetween the first and second holders, the cable adapted to couple thebattery to the control module.
 41. The support system of claim 40 ,further comprising a connector situated within the second holder adaptedto couple the battery to the cable.